An energy dispersion x-ray detector (EDX) may be used for determining a composition of a microscopic element. An energy dispersion x-ray detector collects x-ray photons emitted as a result of an illumination of the microscopic element and generates an energy spectrum. Energy spectrum means any type of information about energy levels at different wavelengths or frequencies along the spectrum. For example—the energy spectrum can be a histogram that displays the number of X-ray counts for each x-ray energy level. Measuring X ray energies may help to characterize the element from which an x-ray photon was emitted.
Prior art energy dispersion x-ray (EDX) detectors have a limited energy resolution and may be incapable of differentiating between materials (referred to as “materials of ambiguous EDX composition determination”) that have energy peaks that differ from each other by an energy difference that is smaller than the energy resolution of the energy dispersion x-ray detector.
For example, Iron (Fe) and Fluorine (F) form a group of materials of ambiguous EDX composition determination. Iron has a characteristic energy peak at 709 eV (“L line”), and Fluorine has a characteristic energy peak at 677 eV. The difference between these energy peaks is 32 eV. An energy dispersive x-ray detector that has an energy resolution of 70 eV cannot distinguish between Iron and Fluorine.
An energy spectrum generated by an energy dispersion x-ray is analyzed by searching for energy peaks that correspond to characteristic energy levels of different materials. The outcome of the analysis is an estimate of the composition of the microscopic element. The estimate of the composition of the microscopic element may be inaccurate when the energy spectrum includes a peak that is attributed to an material of ambiguous EDX composition determination.
Nowadays, EDX is limited and cannot characterize elements that have overlapping x ray peaks. Different techniques can be used, such as wavelength dispersive x-ray spectrometer (WDS), Auger spectrometer and micro-calorimeter. However, the above are either slow or more complicated to integrate onto an in-line platform in the analysis industry.
There is a growing need to improve the accuracy of composition analysis that is based upon an energy spectrum generated by the energy dispersive x-ray detector.